CN117940085A - Teleoperated robotic system for surgery - Google Patents
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- CN117940085A CN117940085A CN202280056032.6A CN202280056032A CN117940085A CN 117940085 A CN117940085 A CN 117940085A CN 202280056032 A CN202280056032 A CN 202280056032A CN 117940085 A CN117940085 A CN 117940085A
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Abstract
A method of teleoperational preparation in a teleoperated robotic surgical system 1 is described, performed during non-operational steps, wherein the system does not perform teleoperation. The above-described robotic system 1 to which the method is applicable comprises a plurality of motor-actuators 11, 12, 13, 14, 15, 16 and at least one surgical instrument 20. The surgical instrument 20 further includes an articulating end effector 40 having at least one degree of freedom (P, Y, G). The surgical instrument 20 further includes at least one pair of antagonistic tendons (31, 32), (33, 34), (35, 36) mounted in the surgical instrument 20 described above so as to be operatively connected or connectable to separate connectors (or rigid connection elements) of the motor actuator and end effector 40. The pair of antagonistic tendons is configured to actuate at least one degree of freedom associated therewith between the at least one degree of freedom P, Y, G to thereby determine an antagonistic effect. The method comprises the following steps: (i) A single correlation is established between a set of motions of the motor actuators 11, 12, 13, 14, 15, 16 of the robotic system 1 and respective motions of the articulating end effector 40 of the surgical instrument 20. (ii) performing a holding step comprising, in order: applying a tensile stress to at least one pair of antagonistic tendons (31, 32), (33, 34), (35, 36) and maintaining such tendons in a tensile stress state by applying a holding force Fhold to the tendons, the holding force being adapted to determine a loaded state of the tendons; providing a command indicating intent to enter a remote operation; allowing the surgical instrument (20) to be accessed in a teleoperational state. In addition, a corresponding teleoperated robotic surgical system is also described.
Description
Technical Field
The present invention relates to a method for preparing a teleoperation in a teleoperated robotic surgical system and a related robotic system.
Accordingly, the present specification relates more generally to the technical field of operation control of robotic systems for teleoperated surgery.
Background
In teleoperated robotic surgical systems, actuation of one or more degrees of freedom of the slave surgical instruments is typically subject to one or more master control devices configured to receive commands issued by the surgeon. Such master-slave control structures typically include a control unit that may be housed in an automatic surgical robot.
Known articulated surgical instruments for robotic surgical systems include actuation tendons or cables to transfer motion from an actuator, which is operatively connected to a rear end portion of the surgical instrument (actuation interface), distally to the tip of the surgical instrument, the latter being intended to operate and/or manipulate a surgical needle on a patient anatomy, as shown for example in documents WO-2017-064301 and WO-2018-189729 under the same applicant. Such a document discloses a solution in which a pair of antagonistic tendons is configured to achieve the same degree of freedom as a surgical instrument. For example, the rotational joints (pitch and yaw degrees of freedom) of the surgical instrument are controlled by applying tension applied by the pair of antagonistic tendons.
For example, document WO-2014-070980 shows a surgical instrument with a rear end portion having a capstan which winds two antagonistic movement tendons of the degree of freedom of the surgical instrument in opposite directions. The preloaded spring exerts a resilient influence to keep the tendon taut.
It is also known that surgical instruments in which the same pair of tendons is capable of actuating more than one degree of freedom simultaneously, such as shown in WO-2010-009221, wherein only two pairs of tendons are configured to control three degrees of freedom of the surgical instrument.
Typically, tendons used in robotic surgery are made in the form of wires (or strands) and wound on pulleys mounted along the surgical instrument. Each tendon may be mounted on an instrument that has been spring preloaded, i.e. pre-adjusted prior to assembly onto the instrument, such that each tendon is always in tension, in order to provide a quick actuation response of the degree of freedom of the surgical instrument when activated by the actuator, and thus to provide good control of the degree of freedom of the surgical instrument.
Generally, all cords are subject to elongation when loaded. Under load, the new entangled core wire typically has a high elongation of plastic-elastic nature due at least in part to the unraveling of the fibers forming the core wire.
For this reason, prior to assembly onto a surgical instrument, it is common practice to subject the new tendon to a high initial load in order to remove the residual plasticity of the pulling and entanglement process or the material itself.
The core wire typically has three elongated elements:
(1) Elastic elongation deformation, which recovers when the tensile load ceases;
(2) Recoverable deformation, i.e., a relatively small deformation that gradually recovers over a period of time, and is generally a function of the entanglement properties, and may take between hours and days when not subjected to any load;
(3) Unrecoverable permanent elongation.
As mentioned above, permanent elongation deformation may be achieved by a core wire breaking process performed prior to assembly on the instrument, which may include loading and unloading cycles, and involve plastic elongation deformation of the fiber itself.
Viscous creep deformation under tensile load is a time-dependent effect that affects some types of entangled core wire when subjected to fatigue and may be recoverable or non-recoverable, generally depending on the strength of the applied load.
In general, the fatigue properties of polymer fibers differ from those of metal fibers in that polymer fibers do not yield to crack propagation failure as do metal fibers, although cyclic stresses may lead to other forms of failure.
WO-2017-064306 under the same applicant shows a solution for a very small surgical instrument for robotic surgery, which uses tendons adapted to support a high radius of curvature and at the same time to slide on the surface of a rigid element (commonly called "link") forming the hinge/articulation tip of the surgical instrument. To allow such sliding of tendons, the tendon-connector sliding friction coefficient must be kept as low as possible, and the above document teaches the use of tendons formed from polymer fibers (rather than using steel tendons).
Although advantageous from many points of view, in practice as a practical result of the miniaturization of surgical instruments obtained by means of the use of the above-mentioned tendons formed from polymer fibers, in the context of this solution it becomes more important to avoid the occurrence of elongations or contractions (contractions) of the tendons in the operating state of the surgical instrument, since the uncontrollable effect of small surgical instruments becomes stronger with a reduction in size with the same variation in length.
The metal tendons have a moderate recoverable elongation and the pre-load procedure performed above, performed prior to assembly on the surgical instrument, is generally sufficient to completely remove the residual plasticity, while the pre-loads they are subjected to remain immediately reactive in use at the time of assembly.
For example, document US-2018-0228563 shows a strategy comprising: in preparation for remote operation, the two antagonistic tendons are placed independently in tension and then the two tendon antagonistic actuators are mechanically coupled to obtain tendon tensioning to provide a rapid response when stressed in the operational state.
In addition, tendons made of polymeric materials have high elongation due to the above contributions; furthermore, if the pre-load process is performed prior to assembly, the tendon is not immediately prevented from rapidly recovering a significant portion of the recoverable elongation when the tendon is subjected to a low tensile load. If on the one hand any high prediction of the assembly preload prevents the recovery of deformation, on the other hand the creep process of the polymer tendon is exacerbated even when not in use, forcing the tendon to stretch and weaken almost indefinitely, which is not a viable strategy.
For example, interwoven cords formed of high molecular weight polyethylene fibers (HMWPE, UHMWPE) are generally subject to non-recoverable deformations, while aramids, polyesters, liquid crystalline polymers (liquid crystal polymers, LCP), PBOAnd nylon are less affected by this feature.
In the case of surgical instruments, the variation of the tendon length and the recovery of elongation due to the above-mentioned phenomenon of tendon elongation are highly undesirable, especially when in an operative state, because it necessarily imposes objective complications in control to maintain a sufficient level of precision and accuracy of the surgical instrument itself.
As another example of background art, reference may be made to US patent application US-2020-0054403, which shows an engagement process of a surgical instrument at an actuation interface of a robotic system, wherein a motorized rotating disc of the robotic system is engaged with a corresponding rotating disc of the surgical instrument, which in turn is connected to a degree of freedom actuation cable of an end effector of the surgical instrument. The described engagement process allows for identifying whether a surgical instrument is operably engaged with a robotic system to evaluate a response perceived by a motorized rotating disk of the robotic system.
Thus, it is briefly stated that there is a need to avoid or at least minimize extension or restoration of the actuation tendons of one or more degrees of freedom of the surgical instrument during use or over time, and to avoid or at least minimize lost motion caused by undesired extension or restoration of the tendons in the operative state, such as entering a new teleoperational state during teleoperation or after a period of non-teleoperation (not mandatory), without imposing for this reason the dimensions of the surgical instrument, in particular for the distal hinge/articulation thereof.
At the same time, it is desirable to provide a solution which, although simple, is capable of ensuring a high level of controllability of the surgical instrument, so that it is reliable in the operating state (such as during remote operation) and at the same time does not hamper miniaturization of the surgical instrument, in particular at its terminal hinge/articulation portion.
SUMMARY
It is an object of the present invention to provide a method of teleoperational preparation in a teleoperated robotic surgical system which allows to at least partially overcome the drawbacks set forth above with reference to the background art and in response to the above-mentioned needs which are particularly felt in the technical field under consideration. Such an object is achieved by a method according to claim 1.
Further embodiments of such a method are defined by claims 2-29.
It is a further object of the present invention to provide a teleoperated robotic surgical system capable of performing and/or adapted to be controlled by the above method. Such an object is achieved by a system according to claim 30.
Further embodiments of such a system are defined by claims 31-49.
More specifically, the object of the present invention is to provide a solution meeting the above technical requirements, the characteristics of which are summarized below.
In general, a possible procedure for preparing for teleoperation is shown in fig. 10, in which there is mentioned the steps of engaging a surgical instrument, adjusting (also called "pre-adjusting" step) and alternately holding and teleoperating. The present disclosure is particularly focused on the latter. For example, the steps of engaging, adjusting and holding may be in a state in which the robotic system is autonomous, i.e. not remotely operated.
In fact, with the proposed solution, a remote operation preparation step including a remote operation preparation holding process can be performed.
Hereinafter, reference will be made to the "holding process" of the preparation step, and the term (equivalent to the "holding step" for the purposes of the present disclosure) will also be used.
The above-described teleoperation preparation steps including the holding procedure are preferably performed before each teleoperation step in which the at least one surgical instrument of the slave device completely follows (i.e. completely slave-tracks) the at least one master device.
The holding process may be performed after an initialization step including an initial engagement process in which the surgical instrument is engaged to the slave robotic platform and before a teleoperational step.
The holding process may be performed after an initialization step comprising an initial adjustment step in which the surgical instrument is subjected to adjustment of its tendons (also called "pretensioning") and before a teleoperation step.
The holding process may be performed between two adjacent teleoperational steps, such as between the end of one teleoperational step and the beginning of the next teleoperational step.
For example, between two adjacent teleoperational steps, an intermediate step may be inserted in which the surgical instrument of the slave device does not follow the master device, such as a paused teleoperational step and/or a limited teleoperational step and/or an adjustment step and/or a rest step.
In view of the above, the first holding step may be performed after the initializing step including the adjusting step and before the first remote operation step; further, the second holding step may be performed between the above-described first remote operation step and a second remote operation step following the first remote operation step. Thus, those skilled in the art will appreciate that further holding steps may be performed at the end of each teleoperational step and prior to subsequent successive teleoperational steps. The number of consecutive and adjacent teleoperational steps that can be performed during a teleoperational robotic surgical operation can depend on various contingent and specific requirements.
In other words, after an initialization step comprising a joining process and a conditioning process, one or more cycles are performed, which comprise a holding step and a remote operation step following the holding step.
Performing at least one holding step allows the tendons of the surgical instrument to be held in a tensile stress state upon entering the teleoperational step, thereby ensuring a fast response of the tendons.
For example, at the end of the initialization step comprising the above-mentioned adjustment procedure, the execution of the holding step allows avoiding the relaxation of the tendons due to the remote operation step, thereby maintaining the adjustment level of the tendons reached during the adjustment step ("pretensioning").
By means of the holding step, the reference position of the actuator and/or the transmission element of the surgical instrument from the robotic system may be rebalanced at the end of the teleoperational step during which the tendons of the surgical instrument may change their length, for example due to sliding friction and/or restoration of recoverable deformations.
In fact, during the teleoperation step in which the surgical instrument completely follows the main device, it may happen that the performance of at least some tendons undergoes degradation due to a strong actuation of the degrees of freedom of the surgical instrument, as it may be required for the tendons to describe an actuation of a high radius of curvature (such as the degrees of freedom of reference pitch/yaw).
Alternatively or additionally, a long-term and relatively high level of stretching of a subset of tendons (e.g., one or two pairs of antagonistic tendons to maintain a long-term grip state or "grip" of the tip of the surgical instrument on the surgical needle and/or biological tissue) may occur during the teleoperational step. This, in addition to the performance degradation of the two antagonistic tendons connected to the gripping freedom, can also cause a kinematic imbalance due to the fact that a subset of the total number of tendons is subjected to a more intense actuation.
Performance degradation may increase with increasing duration of the teleoperational step and with increasing duration of the long-term grip state.
Applying relatively high tension on the tendon may have the undesirable effect of causing the cross section of the tendon to flatten, and this may lead to an increase in the contact surface of the tendon on the sliding surface (e.g. the surface of the connector of the articulating surgical instrument), which in turn causes an increase in friction, more significantly causing a degradation of the tendon performance.
The holding step preferably ends orderly with the application of a relatively low force to avoid such flattening/crushing of the tendons prior to entering the teleoperation step.
Otherwise, during the holding step, the surgical instrument preferably does not follow the main device, and thus from a kinematic point of view, the surgical instrument may be held in a stationary state.
By the proposed solution, recoverable elongation from at least one tendon to actuate the degree of freedom of the surgical instrument can be eliminated or at least minimized, and an accurate transfer of the actuation action exerted on the tendon can be obtained even if the remote operation is interrupted and/or paused.
By the proposed solution, restoration of recoverable elongation of the at least one tendon to actuate the degree of freedom of the surgical instrument can be eliminated or at least minimized, and an accurate and stable transfer of the actuation action can be obtained during the subsequent teleoperation step, even if the teleoperation has been interrupted and/or paused before.
With the proposed solution, an improved accuracy of the kinematic correspondence between master and slave is provided during remote operation and during two adjacent remote operation steps.
By means of the proposed solution, idling due to undesired lengthening of the tendons in the operating state is avoided or at least reduced to a minimum.
With the proposed solution, a satisfactory stability of the physical characteristics of the surgical instrument is provided.
By the proposed solution, an improved control of the degree of freedom of the surgical instrument is provided.
Drawings
Further features and advantages of the method according to the invention will become apparent from the following description of a preferred exemplary embodiment, given by way of non-limiting indication with reference to the accompanying drawings, in which:
figure 1 shows an isometric view of a robotic system for teleoperated surgery according to one embodiment;
Figure 2 shows an isometric view of a part of a robotic system for teleoperated surgery of figure 1;
figure 3 shows an isometric view of a distal portion of a robotic manipulator according to one embodiment;
Fig. 4 shows an isometric view of a surgical instrument according to an embodiment, wherein tendons are schematically shown in dashed lines;
FIG. 5 schematically shows a plan view and a partial cross-sectional view of the actuation of the articulation end effector apparatus (or end effector) of a surgical instrument according to possible modes of operation, for clarity;
Fig. 6 is a schematic diagram illustrating possible adjustment steps of the method of remote operation preparation according to the possible modes of operation, taking the example illustrated in fig. 5 as an example;
Fig. 7 schematically shows the actuation of the degrees of freedom of the articulated end effector apparatus of the surgical instrument according to possible modes of operation;
8A, 8B, 8C and 8D show, respectively, curves of the time trend of the application of force to the motor actuator as a function of time under various sequences of steps according to the operating mode;
fig. 9 shows a schematic cross-section of a part of an actuated surgical instrument and a part of a robotic manipulator according to degrees of freedom of the surgical instrument in possible modes of operation;
Fig. 10 is a flow chart showing the steps of a method comprising preparation for remote operation and remote operation according to possible modes of operation;
Fig. 11 and 12 are two flowcharts showing the steps of a method for remote operation preparation and remote operation according to two respective possible modes of operation;
fig. 13 shows an isometric view of the end device of a surgical instrument according to one embodiment of the invention, and the gripping actions performed by two pairs of antagonistic tendons according to the possible modes of operation.
Detailed Description
Referring to fig. 1-13, a method of teleoperational preparation in a surgical teleoperational robotic system 1 is described, which method is to be performed during non-operational steps, wherein the system does not perform teleoperation.
The above-described robotic system 1 to which the method is applicable comprises a plurality of motor-actuators 11, 12, 13, 14, 15, 16 and at least one surgical instrument 20.
The surgical instrument 20 further includes an articulating end effector device 40 (i.e., an articulating tip 40) having at least one degree of freedom (P, Y, G). The articulating end effector apparatus 40 is also commonly referred to as an "articulating end apparatus" or "articulating end effector" or "hinge end effector" (such definition will be used as synonym hereinafter).
The surgical instrument 20 further includes at least one pair of antagonistic tendons (31, 32), (33, 34), (35, 36) mounted in the surgical instrument 20 described above for operative connection or connectable to corresponding connectors (or rigid connection elements) of the motor actuator and end effector apparatus 40. The tendons of the pair of antagonistic tendons are configured to actuate/implement at least one degree of freedom related thereto among the at least one degree of freedom P, Y, G, thereby determining an antagonistic effect.
The method comprises the following steps:
(i) Establishing a single correlation between a set of motions of the motor actuators 11, 12, 13, 14, 15, 16 of the robotic system 1 and corresponding motions of the articulating end effector apparatus 40 of the surgical instrument 20;
(ii) Sequentially performing the maintaining step, including:
-stressing at least one pair of antagonistic tendons (31, 32), (33, 34), (35, 36) by tensile stress, and maintaining such tendons in a tensile stress state by applying a holding force Fhold (e.g. by means of a feedback control loop) to the tendons, which is suitable for determining the loading state of the tendons; the stressing step is determined by a motor actuator;
-providing a command indicating a willingness to enter a remote operation;
Enabling the surgical instrument 20 to enter a teleoperational state.
According to an embodiment, the method is applied to a surgical instrument 20, which further comprises a plurality of transmission elements 21, 22, 23, 24, 25, 26, each operatively connected to a respective at least one motor actuator 11, 12, 13, 14, 15, 16.
In this case, the above-mentioned stressing step is performed by the transmission element 21, 22, 23, 24, 25, 26, which is operated and controlled by the respective motor actuator.
In other words, the transmission system of the surgical instrument 20 for transmitting the actions applied by the motor actuators comprises said tendons and preferably also said transmission elements interfacing with the respective motor actuators of the robotic manipulator.
The transmission element is preferably a rigid element. So that the action of the electromechanical actuator is transmitted to the respective tendons without attenuation/distortion that might otherwise be introduced, for example if the transmission element is an elastic and/or damping element.
According to an embodiment, the operative connection between the tendons of the surgical instrument and the respective motor actuators may be a releasable connection.
According to an embodiment, the operative connection between the tendons of the surgical instrument and the respective motor actuators may be a direct or indirect connection, for example by inserting respective transmission elements which may be connected to the tendons.
According to an embodiment, after steps (i) - (ii), the method comprises step (iii) of performing a teleoperation by means of the surgical instrument 20 of the robotic system (1).
According to an embodiment of the method, the steps of maintaining (ii) and teleoperation (iii) are repeated such that the maintaining step (ii) is performed between two adjacent teleoperation steps (iii).
According to an embodiment of the method, wherein the kinematic null of each of the electromechanical actuators 11, 12, 13, 14, 15, 16 is defined, during the maintaining step (ii) and after the above-mentioned step of stressing at least one pair of antagonistic tendons, the method comprises: a further step of storing the possible positional offset of each electromechanical actuator 11, 12, 13, 14, 15, 16 with respect to the corresponding stored kinematic zero.
According to an embodiment of the method, during the maintaining step (ii), the step of stressing the at least one pair of antagonistic tendons comprises at least one loading and unloading cycle, wherein each loading and unloading cycle comprises applying a high force Fhold to determine the loaded state of the pair of tendons and applying a low force Flow to determine the unloaded state of the pair of tendons.
In this case, such a high force corresponds to the holding force Fhold, and such a low force Flow is a force lower than the holding force Fhold.
According to an embodiment, in each of the above-described loading and unloading cycles, a low force Flow is first applied, followed by a high or holding force Fhold.
According to an embodiment, during the holding step (ii), between the step of providing a command indicating a willingness to enter a teleoperation and the step of enabling to enter a teleoperation state, a further step of applying the above-mentioned low-force Flow to the tendons is provided, so as to apply a tensile stress to the tendons according to the unloading state of the above-mentioned loading and unloading cycles.
According to an embodiment, the method comprises the further steps of: the force applied to all tendons is detected upon exiting the teleoperation step, a minimum force Fmin is identified among the detected forces, and then all tendons are put in an intermediate stress state corresponding to the minimum force value Fmin.
It should be noted that such a force Fmin (so called Fmin because it is the lower of all forces detected at the exit from the teleoperation) corresponds to an intermediate stress state, which then puts all tendons at an intermediate force value Fmin between a low force value and a high force value: flow < Fmin < Fhold
As already noted, as also shown in the example of fig. 8B, the intermediate stress Fmin is recorded upon exiting the remote operation.
Thus, maintaining the holding forces "low" and equal to each other avoids the drawbacks of inadvertently moving the degrees of freedom of "pitch", "yaw" and "grip" of the articulating end effector 40 during the holding step.
According to a possible embodiment, the method further preferably comprises: a subsequent step of putting all tendons in an unloading stress state corresponding to the low-force Flow; and/or a subsequent step of placing all tendons in a loaded stress state corresponding to the high retention force Fhold.
According to an embodiment, the above-mentioned step of putting all tendons in an intermediate stress state corresponding to the minimum force value Fmin is: following a specific and/or different loading and/or unloading curve for each tendon is performed as a function of the detected starting force value for each tendon.
According to an embodiment, the above step of applying the retaining force Fhold to the tendon comprises:
-placing all tendons in an intermediate stress state corresponding to the above mentioned minimum force value Fmin, wherein each tendon is according to a respective specific load curve depending on the respective detected starting force value such that the load is equally divided between antagonistic tendons of one or more pairs of antagonistic tendons;
All tendons are then put in a loaded stress state corresponding to the above mentioned holding force Fhold.
According to an embodiment of the method, the teleoperation step starts with a predefinable teleoperation initiation force Fwork being applied to the tendon, which initiation force Fwork is lower than the high retention value Fhold described above.
According to an embodiment, the above-described predeterminable remote operation starting force Fwork is substantially equal to the low holding force Flow, i.e., fwork =flow.
According to an embodiment, the transition between the high holding force Fhold and the remote-operation initiating force Fwork is preferably controlled by the user by activating the control pedal.
Such a stress sequence is shown in fig. 8A, where it can be observed that after each holding step, the force is reduced to a level Flow at which the remote operation is initiated. The falling front from high force Fhold to low force Flow to initiate remote operation is controlled by a control pedal activated by the user so that entry of remote operation is always intentional. Conversely, the exit from the remote operation may be intentionally activated by the user with the aid of a pedal, or independently controlled by the robot, for example after an abnormality is detected by inspection.
It should also be noted that in this embodiment, when subjected to various tensile states, the low and high forces determine the following effects from the point of view of tendon behavior:
the low force Flow is ideally the minimum contact force that can be registered between the motor actuator 11 and the corresponding tendon 31 (or between the motor actuator and the corresponding transmission element 21) so as to sense the contact; however, low force Flow does not determine actuation of the degrees of freedom of the end effector apparatus as described above;
The high force Fhold is a holding force provided and maintained in order to avoid relaxation (i.e. restoration of the deformed state of the tendon).
According to an embodiment of the method, the above-mentioned step of stressing the tendons comprises measuring or detecting the forces acting on the tendons during the loading cycles and the holding force value Fhold is reached by the motor-actuator by a feedback force control process based on the detected or measured actual forces acting on the tendons.
For example, the effective force acting on the tendons is detected or measured by force sensors 17, 18 placed at the distal interface of the motor actuator in order to detect the contact force between the motor actuator and the transmission element when provided.
According to an embodiment of the method, the above-mentioned step of stressing the tendons comprises measuring or detecting forces acting on the tendons during the unloading period, and the low force value Flow is reached by the motor actuator by a feedback force control process based on the detected or measured actual forces acting on the tendons.
According to another embodiment of the method, the above-mentioned step of stressing the tendons comprises measuring or detecting a positional shift of the transmission element 21, 22, 23, 24, 25, 26 or the motor actuator 11, 12, 13, 14, 15, 16 relative to a respective initial value predetermined or stored at the end of a previous remote operation step, and performing a loading cycle by the motor actuator by a feedback position control procedure based on the detected, measured or stored above-mentioned positional shift.
According to an embodiment of the method, the above-mentioned step of stressing the tendons comprises measuring or detecting a positional shift of the transmission element 21, 22, 23, 24, 25, 26 or the motor actuator 11, 12, 13, 14, 15, 16 with respect to a respective initial value predetermined or stored at the end of a previous remote operation step, and performing an unloading cycle by the motor actuator by means of a feedback position control procedure based on the detected, measured or stored above-mentioned positional shift.
According to an embodiment of the method, during the holding step (ii), the at least one pair of tendons are stressed by means of a loaded state corresponding to a gripping action of the end effector apparatus 40 of the surgical instrument 20 such that the surgical instrument is in a gripped state during the holding step.
This embodiment (which may be defined as "holding squeeze (hold squeeze)", i.e. holding) is preferably performed in a holding step that occurs between two adjacent teleoperational steps, wherein upon withdrawal of a first teleoperational step the surgical instrument 20 is in a gripping or grasping state, e.g. on a surgical needle and/or biological tissue, which grasping also has to be held during a subsequent holding step ready for the next teleoperational step (see the illustrations of fig. 8C and 8D in this regard).
According to an embodiment of the method, the above step (ii) comprising a loading and unloading cycle is performed only on a subset of tendons that do not involve actuation of the gripping degrees of freedom.
Preferably, this approach is implemented in conjunction with the "hold-down" embodiment described above, which includes exiting the remote operation while articulating end effector 40 is grasping a needle or tissue.
Typically, the gripping action affects four tendons (i.e., two pairs of antagonistic tendons such as 33-34 and 35-36 shown in fig. 13), but depending on the variation possible, there may be only two affected tendons.
According to the embodiment shown in fig. 8C, the loading and unloading cycles are not performed, but the motor actuator of the tendon involved in the gripping is simply deactivated ("motor frozen") -resulting in a reduction of the force, as shown in fig. 8C, so that the tendon remains gripped on the gripped object.
According to another preferred embodiment, as shown in fig. 8D, in the grip state performed, the application of the grip force is also maintained at the time of withdrawal from the remote operation.
According to an embodiment of the method, the robotic system 1 comprises a control device 9, which control device 9 is configured to control the motor actuators 11, 12, 13, 14, 15, 16, preferably by means of the transmission elements 21, 22, 23, 24, 25, 26, to apply a controlled movement and to apply a controlled force to the tendons.
An embodiment according to such an example, wherein the kinematic zero position of each motor-actuator 11, 12, 13, 14, 15, 16 is defined, and wherein the method is adapted to a non-operational step between two remote operation periods of the robotic system 1, the method comprising the further steps at the beginning of the non-operational step of:
Storing the position of the end effector apparatus 40 at the end of the previous teleoperation step relative to the kinematic zero as the known kinematic position of the end effector apparatus 40 of the surgical instrument 20, wherein the known kinematic position of each transmission element POS kin-off corresponds to this position;
-retracting the motor actuators 11, 12, 13, 14, 15, 16 to remove, for each transmission element 21, 22, 23, 24, 25, 26, the respective positional offset generated in the previous remote operation step;
-applying a respective recalibration force F on each transmission element 21, 22, 23, 24, 25, 26 continuously during the whole non-operative step of the surgical instrument by means of a feedback control configured to keep the recalibration force F constant, so as to determine on each transmission element 21, 22, 23, 24, 25, 26 a respective positional offset POS FC (t) resulting from the application of the above-mentioned respective recalibration force F
In this case, at the end of the non-operative step, at the beginning of the next remote operative step, the method comprises the further steps of:
Stopping the application of the recalibration force F to each transmission element 21, 22, 23, 24, 25, 26;
-measuring and storing the determined position offset POS FC-off on each transmission element 21, 22, 23, 24, 25, 26 at the end of the non-operational step, followed by the application of a recalibration force during the immediately end of the non-operational step, and correlating the recorded position offset POS FC-off for each transmission element 21, 22, 23, 24, 25, 26 to the above-mentioned known kinematic position of the end device 40;
-applying an operating and a moving force commanded by the control device 9, the control device 9 being configured to determine the control force based on the operator's command and taking into account the above-mentioned stored position offset POS FC-off of each transmission element 21, 22, 23, 24, 25, 26.
According to an embodiment, the above mentioned recalibration force F corresponds to the holding force Fhold.
According to an embodiment, the step of applying a recalibration force on each transmission element comprises: the force is applied to the transmission element by means of a feedback loop, wherein the feedback signal corresponds to the force applied to the transmission element that is actually detected by a corresponding force sensor operatively connected or connectable to the transmission element.
According to an embodiment, the kinematic zero comprises a fixed offset PRESTRECH off caused by another step of pre-conditioning the surgical instrument performed prior to use of the surgical instrument.
According to a specific embodiment, the preconditioning step described above provides:
(i) Locking at least one of the at least one degrees of freedom P, Y, G of the end effector apparatus 40;
(ii) The tensile stress is applied to the respective at least one tendon operatively connected to the at least one locked degree of freedom by applying an adjusting force Fref to the respective transmission element 21, 22, 23, 24, 25, 26 connected to the respective tendon to which the tensile stress is to be applied according to at least one time period. The application of the adjustment force Fref is performed by the respective motor actuator to stress the respective tendons.
Such at least one time period includes: at least one low load period, wherein a low adjustment force Flow is applied to the transmission element, which results in a corresponding low tensile load on the corresponding tendons; and at least one high load period, wherein a high adjustment force Fhigh is applied to the transmission element, which results in a corresponding high tensile load on the corresponding tendon.
The high adjustment force Fhigh may take on increasing values in two adjacent time periods. In other words, a plurality of said time periods is provided, wherein the respective value of the high adjustment force Fhigh increases during at least two adjacent time periods.
In the adjusting (preconditioning) step, a plurality of N time periods may be provided in order to determine an alternation between successive low load periods Flow and high load periods Fhigh, wherein a respective low adjusting force flow_n is applied during the low load period of the nth period, and wherein a respective high adjusting force Fhigh _n is applied during the high load period of the nth period.
According to an embodiment, the low adjustment force flow_n for different time periods corresponds to the same predetermined low adjustment force value Flow and the high adjustment force Fhigh _n corresponds to a progressively increasing high adjustment force value until a maximum high force value Fhigh _max is reached.
According to an embodiment, the high adjustment force value for the nth time period is calculated according to the following formula:
Where N is the current period, N is the total number of periods, nc is the number of periods at constant Fhigh, fhigh _max is a settable value.
According to an embodiment, during the time period: (i) Each of the at least one low load period has a first duration and comprises a first holding sub-step having a first holding duration during which a first force value corresponding to the low adjustment force Flow is applied; (ii) Each of the at least one high load period has a second duration and comprises a second holding sub-step having a second holding duration during which a second force value corresponding to the high adjustment force Fhigh is applied. According to an embodiment, the first duration comprises, in addition to a first holding sub-step having a first holding duration, a first ramp sub-step having a first ramp duration such that the sum of the first holding duration and the first ramp duration corresponds to the first duration; and, the second duration includes a second ramp sub-step having a second ramp duration in addition to the second holding sub-step having a second holding duration, such that a sum of the second holding duration and the second ramp duration corresponds to the second duration, and wherein the first holding duration is greater than the first ramp duration and the second holding duration is greater than the second ramp duration. According to an embodiment, the first duration is in the range of 0.2 seconds to 30.0 seconds and the second duration is in the range of 0.2 seconds to 5.0 seconds. Preferably, the first duration is in the range of 1.0 seconds to 3.0 seconds and the second duration is in the range of 1.0 seconds to 3.0 seconds. According to an embodiment, the first ramp duration is in the range of 0.2 seconds to 10.0 seconds and the second ramp duration is in the range of 0.2 seconds to 2.0 seconds. According to an embodiment, the first holding time is in the range of 0.2 seconds to 20.0 seconds and the second holding time is in the range of 0.2 seconds to 3.0 seconds.
According to an embodiment, in the preconditioning step, the low conditioning force Flow has a value in the range of 0.2N to 3.0N, and the high conditioning force Fhigh has a value in the range of 8.0N to 50.0N. Preferably, the low adjustment force Flow has a value in the range of 1.0N to 3.0N, and the high adjustment force Fhigh has a value in the range of 10.0N to 20.0N.
The number N of time periods of the preconditioning step is in the range of 1 to 30, and preferably said number N of time periods is in the range of 1 to 15, e.g. less than 10, and/or more preferably said number N of time periods is in the range of 3 to 8.
As described above, in the embodiment in which the transmission element is not provided, the low adjustment force Flow and the high adjustment force Fhigh are applied to the tendons.
According to an embodiment of the method, the step of retracting the motor actuator described above comprises removing any positional offset resulting from a further possible compensation step of the conveyor system.
According to an embodiment, the holding force Fhold and/or the recalibration force F is in the range of 0.1N to 5N.
According to an embodiment, the positional offset must be less than the maximum allowable positional offset dxA, for example in the range of 1mm to 5mm.
According to an embodiment, the method is applicable in case the tendon is a polymer tendon made of interwoven or braided polymer fibers.
According to an embodiment, the tendon is non-elastically deformed.
According to an embodiment, the method is applicable to a robotic system consisting of a robotic system for teleoperation of a microsurgical instrument, wherein the surgical instrument is a microsurgical instrument.
Referring again to fig. 1-13, further illustrations of surgical instruments to which the methods of the present invention are applied will be provided below, which will aid in a better understanding of the method itself, as well as providing further details on some embodiments of the method by way of non-limiting example.
Some illustrative details regarding the preconditioning step or "pretension" described above are provided herein.
As shown, for example, in the sequence of fig. 5 and 6, a constraining body 37 (shown here as retractable along the shaft or rod 27 of the surgical instrument 20) may be adapted on the articulating end effector device 40 to lock one or more degrees of freedom (in the example shown, the pitch degree of freedom P is locked) in order to facilitate performance of the adjustment procedure.
According to an embodiment, a constraining body 37 is provided for temporarily locking the articulation tip 40 in a predetermined configuration. The constraining body 37 may be retracted along the shaft 27 of the surgical instrument 20. The constraining body 37 may be a plug 37 or a cap 37 that is not retractable along the shaft 27 of the surgical instrument 20 and may be distally removable, for example, with respect to the free end of the articulating end effector device (end effector) 40.
According to an embodiment, at least one actuator 11, 12, 13, 14, 15, 16 is a linear actuator. In this case, at least one of the transmission elements 21, 22, 23, 24, 25, 26 may be a linear transmission element, such as a piston adapted to move along a substantially straight path x-x, as shown in fig. 9.
According to another embodiment, the at least one actuator is a rotary actuator, such as a winch. The at least one transmission element may be a rotary transmission element, such as a cam and/or a pulley.
Articulating end effector apparatus 40 preferably includes a plurality of links 41, 42, 43, 44 (e.g., rigid connecting elements). At least some of such connectors (e.g., connectors 42, 43, 44 in fig. 13) are connected to the mating antagonistic tendons 31, 32; 33. 34; 35. 36.
As shown in the embodiment example of fig. 13, a pair of antagonistic tendons 31, 32 are mechanically connected to the link 42 to move the link 42 relative to the link 41 about the pitch axis P, wherein the link 41 is shown integrated with the shaft 27 of the surgical instrument 20; the other pair of antagonistic tendons 33, 34 is mechanically connected to a link 43 (shown here with free ends) to move such link 43 relative to link 42 about yaw axis Y; a further pair of antagonistic tendons 35, 36 is mechanically connected to link 44 (shown here with free ends) to move such link 44 relative to link 42 about yaw axis Y; appropriate combined activation of the links 43 and 44 about the yaw axis Y may result in an opening/closing or gripping degree of freedom G. Those skilled in the art will appreciate that the configuration of the tendon and connector and the degree of freedom of the articulating end effector 40 may vary relative to those shown in fig. 13 while remaining within the scope of the present disclosure.
According to an embodiment, three pairs of antagonistic tendons (31, 32), (33, 34), (35, 36) are provided to actuate three degrees of freedom (e.g. degrees of freedom of pitch P, yaw Y and grip G). In this case, the surgical instrument 20 may comprise six transmission elements 21, 22, 23, 24, 25, 26 (e.g. six pistons, as shown in fig. 4, wherein tendons are shown in dashed lines), i.e. three pairs of antagonistic transmission elements (21, 22), (23, 24), (25, 26), e.g. intended to cooperate with three pairs of corresponding antagonistic motor actuators (11, 12) (13, 14), (15, 16).
According to an embodiment, a sterile barrier 19, such as a sterile cloth made of plastic sheet or other surgical sterile cloth material, such as a woven or non-woven fabric, is interposed between at least the motor actuator and the transmission element.
The co-inclusion of the sterile barrier 19 and the sensors 17, 18 placed on the motor actuator upstream of the sterile barrier 19 is particularly advantageous in that it allows the movable components of the control system (also referred to herein as sensors) to be installed in a non-sterile environment, enabling them to be reused for different interventions, avoiding the assembly of such components on the surgical instrument 20, which can be disposable and operate in a sterile environment downstream of the sterile barrier 19.
According to an embodiment, each of the at least one pair of antagonistic polymer tendons (31, 32), (33, 34), (35, 36) is preferably non-elastically deformable, although it may also be elastically deformable.
According to a preferred embodiment, each tendon of at least one pair of antagonistic tendons of the surgical instrument 20 is made of a polymeric material.
Preferably, according to an embodiment, each tendon of the at least one pair of antagonistic tendons comprises a plurality of polymer fibers interwoven and/or braided to form a polymer strand. According to an embodiment, each tendon of the at least one pair of antagonistic tendons comprises a plurality of high molecular weight polyethylene fibers (HMWPE, UHMWPE).
According to embodiments, the at least one tendon may comprise a plurality of aramid fibers and/or polyester and/or liquid crystal polymer (liquid crystal polymers, LCP) and/or PBOAnd/or nylon and/or high molecular weight polyethylene and/or any combination of the above.
According to an embodiment, each of the at least one pair of antagonistic polymer tendons is made partly of a metallic material and partly of a polymer material, e.g. formed by interlacing of metallic fibers and polymer fibers.
A specific embodiment of the method according to the invention, as illustrated in the flow chart of fig. 11, is shown in more detail below by way of a non-limiting example.
In this case, the method includes the following steps reported in the preferred order of execution.
First, an initialization step is provided, which includes the steps of:
Inserting the surgical instrument 20 into a suitable connector or pocket 28 of the robotic manipulator 10;
engaging the surgical instrument 20, wherein the motor actuators 11, 12, 13, 14, 15, 16 of the robotic manipulator 10 are simultaneously moved to abut each respective transmission element 21, 22, 23, 24, 25, 26 of the surgical instrument 20 to avoid moving the articulating tip 40 (i.e., the end effector device 40) of the surgical instrument 20, thereby avoiding actuating the degrees of freedom P, Y of the articulating tip 40;
-performing the step of pre-stretching the tendons 31, 32, 33, 34, 35, 36;
-optionally storing the offset position (PRESTRECH off) of the electromechanical actuator 11, 12, 13, 14, 15, 16 at the end of the pretensioning step. The storing of this parameter PRESTRECH off preferably occurs when the surgical instrument 20 (i.e., the degree of freedom of the articulating tip 40 of the surgical instrument 20) is at a kinematic zero and this allows for a constant reference of the initial position prior to the first teleoperation. Due to the subsequent positional correction of the motor actuators 11, 12, 13, 14, 15, 16, such positions may be used to track the kinematic consistent position between the motor actuators and the degrees of freedom P, Y, G of the surgical instrument 20.
After the above-described initialization step, the method provides a remote operation preparation step including the first holding step application.
The first holding step includes the acts of:
-feedback force control is used independently on the six motor-actuators 11, 12, 13, 14, 15, 16, i.e. on each motor-actuator individually, to maintain the positions of the motor-actuators reached during the pretensioning step and/or the engagement step and the transmission elements 21, 22, 23, 24, 25, 26 adjacent thereto;
-the motor actuator applying a force Fref equal to the minimum force value Flow;
If the detected force Fsens by means of the force sensors 17, 18 corresponds to a minimum force value Flow, the electromechanical actuator applies a force Fref equal to the holding force value Fhold (which is greater than the minimum force value Flow) to maintain the tension on the respective tendon and avoid its relaxation; the retention force value Fhold is preferably determined experimentally and may vary depending on the type of surgical instrument used; such a retention force value Fhold is determined so as to allow to keep the elongation as constant as possible after the first pre-stretching process, i.e. in order to prevent the tendons from undergoing shortening due to the recovery of the elongation deformation of the tendons subjected to the stresses previously, while preventing the tendons from undergoing further elongation due to the phenomenon of reconstruction of the tendon structure;
At this point, the system verifies: the operator has indicated a desire to enter a remote operation ("operation= true"), for example by pressing the control pedal;
-the motor actuator applies the minimum force value Flow again; reapplication of a minimum level of force allows the force to be released into the motion transmitting joint inside the surgical instrument; this allows the friction generated by the tendon-joint coupling to be reduced during teleoperation, and in turn, the reduction of friction reduces the mismatch effect between the master and slave devices of the robotic system during teleoperation;
-if the force Fsens detected by the force sensor 17, 18 corresponds to a minimum force value Flow, the system is able to enter a first teleoperational step;
-storing the offset position of the electromechanical actuator 11, 12, 13, 14, 15, 16 at the end of the pretensioning step (PRESTRECH off).
After the first holding step, the method provides for performing a first remote operation step, wherein:
access and/or access enablement during a teleoperation step is subject to a teleoperation request command ("operation"
= True "), such as by an operator pressing a control pedal;
the remote operation step comprises subjecting (i.e. following) the electromechanical actuator to the respective master device 3, wherein the electromechanical actuator can be moved according to the laws of kinematics and the force control can be disabled.
Subsequently, the first remote operation step is interrupted and the method provides a system for performing a second remote operation preparation step, wherein the second holding step is applied.
The second holding step includes the acts of:
-feedback force control is used independently on the six motor-actuators 11, 12, 13, 14, 15, 16 in order to balance the forces exerted on each transmission element 21, 22, 23, 24, 25, 26 after a change of configuration of the position of the motor-actuator with respect to the corresponding stored offset position at the end of the pretensioning step, according to the following relation:
Mpos(t)＝Prestretchoff+PosKinoff+PosFC(t)
Wherein:
M pos (t) is the position of each motor actuator relative to the motorized reference system, e.g., positioned at the distal end of each motor actuator;
PRESTRETCH off is the stored offset after the pretension process is completed with respect to the motorized reference system described above;
Pos Kinoff is the stored offset from the law of kinematics upon exit from the first teleoperation step;
Pos FC (t) is the displacement of the motor actuator as a function of time, generated by force control.
During this second holding step, the motorized brake positional offset is stored with respect to the corresponding offset position stored at the end of the pretensioning step, namely:
Mpos(t)＝Prestretchoff+PosFCoff+PosKin(t)
Wherein:
pos Kin (t) is the displacement of the electromechanical actuator produced by the kinematic control.
Therefore, the positional shift of the motor actuator stored after the second holding step is expressed by the following formula:
PosFCoff＝Mpos(Tteleop ON)-Prestretchoff-PosKinoff
as described above with reference to the first holding step, the following actions are performed during the second holding step:
-the motor actuator applying a force Fref equal to the minimum force value Flow;
If the force Fsens detected by the force sensors 17, 18 corresponds to a minimum force value Flow, the electromechanical actuator applies a force Fref equal to the holding force value Fhold (which is greater than the minimum force value Flow) to maintain tension on the respective tendons and avoid their relaxation;
At this point, the system verifies: the operator has indicated a desire to enter a remote operation ("operation= true"), for example by pressing the control pedal;
-the motor actuator again applies the minimum force Flow described above;
if the force Fsens detected by the force sensor 17, 18 corresponds to the minimum force value Flow, the system can enter the first teleoperation step.
After the second holding step described above, a second remote operation step is performed, which may be substantially similar to the first remote operation step.
Entering the teleoperational step after performing the holding procedure prepares the surgical instrument 20 for movement in any direction, thereby reducing "lost motion" that may result from the locking of the surgical instrument in configurations in which the motor actuator sticks to the transmission element with different forces.
The alternation between the preparation step (each of which comprises the above-described holding step) and the remote operation step may continue in a deterministic or indeterminate manner.
At the end of the teleoperation steps, and at the end of each teleoperation step, and prior to the holding step, a release step ("release motor offset") may be included, which is entered by means of a command to exit the teleoperation ("operation= false"), such as the release of a control pedal applied by the user, wherein the possibility of teleoperation of the surgical instrument 20 is disabled.
In this release step, the stored motor-actuator position offset (Pos FCoff) is removed. This release step allows to reset any positioning errors previously accumulated in the holding step, allowing to delete possible position drifts, namely:
Mpos(t)＝Prestretchoff+PosKinoff
According to an embodiment, the minimum force value Flow is the minimum force value at which the motor actuator is in contact with (i.e. in abutment with) the transmission element.
According to an embodiment, the retention force value Fhold is a force value that is greater than the minimum force value Flow and is used to maintain tension on and prevent relaxation of the respective tendons 31, 32, 33, 34, 35, 36.
According to several possible embodiments of the method, the above-mentioned value Fhold may be predetermined, i.e. calculated by performing experimental tests on the specific type of tendon used.
The two force values Flow and Fhold may be alternated in order to avoid possible undesired displacement of the end effector device 40 during the holding step. For example, these force values Flow and Fhold alternate as shown in fig. 11 and 12.
According to another embodiment of the method (as described above), any holding step, or even all holding steps, are used instead of feedback force control.
According to an embodiment of the method, when there is a dense actuation of the gripping degrees of freedom (grip, G) at the exit of the teleoperational step, the system performs a holding step taking into account such dense actuation of the gripping degrees of freedom in order to ensure that a kinematic match is maintained, compensating for the elongation of the tendons due to the application of relatively very high gripping forces for a relatively long time. Thus, possible kinematic imbalances due to the fact that only some tendons are subjected to greater stress (e.g., a subset of two to four of the six tendons) than other tendons and thus may be subjected to a greater degree of elongation than other tendons may be avoided.
For example, as shown in fig. 13, the gripping degree of freedom (G) is activated by the action exerted by the two pairs of antagonistic tendons (33, 34) and (35, 36) to maintain a grip on the body 45, which body 45 may be, for example, biological tissue or a surgical needle.
As described above, the holding step does not necessarily include loading and unloading cycles, but may include only the application of a loading state (force Fhold).
According to an embodiment of the method, wherein the surgical instrument 20 exits the teleoperational step in a gripping state (active gripping degree of freedom G, also referred to as "squeeze"), the actuation tendons of such gripping degrees of freedom are subjected to tensile stress. In this case, the holding step comprises applying a loaded state wherein the holding force is at least equal to the grip force. Thereby avoiding a loss of grip.
According to an embodiment, the holding force corresponds to a grip force.
According to an embodiment, if the master device of the teleoperational system recognizes the "squeeze" state, the system recognizes the above-described state (active gripping degree of freedom G) of exiting the teleoperational step in the gripping state.
According to an embodiment, if the force measured on the motor actuator and/or the transmission operatively associated with the actuation tendon of the gripping degree of freedom is greater than a predetermined threshold, the system identifies the above-mentioned state (active gripping degree of freedom G) exiting from the teleoperation step in the gripping state.
According to an embodiment, the holding force may be at least equal to (e.g. corresponds to) the grip force on the actuation tendons of the grip degrees of freedom only. Thus, if the actuation tendon of the grasping degree of freedom is a pair of antagonistic tendons, the system applies a loading state on such a pair of antagonistic tendons, including applying a holding force, avoiding applying loading and unloading cycles.
On the other hand, if the actuation tendon of the grasping degree of freedom is two pairs of antagonistic tendons, the system applies a loading state on such two pairs of antagonistic tendons, including the application of the holding force Fhold, the application of the loading and unloading cycles being avoided.
Alternatively, the holding force may be at least equal to (e.g., corresponds to) the grasping force on all tendons of the surgical instrument 20.
According to various embodiments, wherein the surgical instrument 20 exits the teleoperational step in the gripping state (active gripping degree of freedom G, "squeeze" state) and thus the actuation tendons of such gripping degrees of freedom are under tensile stress, the robot avoids performing a holding procedure/step (the "motor freeze" in fig. 12) on a subset of tendons of the above-mentioned actuation tendons comprising gripping degrees of freedom. In this case, the holding step includes applying the load and unload cycles as previously described.
If the actuation tendon of the grasping degree of freedom is a pair of antagonistic tendons, a holding step on the pair of antagonistic tendons is avoided.
On the other hand, as shown in the example of fig. 13, if the actuation tendons of the grasping degrees of freedom are two pairs of antagonistic tendons, the holding step on the two pairs of antagonistic tendons is avoided, while the holding step is performed on the other tendons (tendons 31 and 32 of fig. 13).
Preferably, the system is adapted to store the withdrawal from the teleoperational step occurring in the gripping state (active gripping degree of freedom G) in order to subsequently compensate (e.g. at the next withdrawal from the teleoperational step) for the failure to perform the holding step on the actuation tendons of the gripping degrees of freedom, thereby performing the holding step.
Referring again to fig. 1-13, a teleoperated robotic surgical system 1 including a plurality of motor-actuators 11, 12, 13, 14, 15, 16, at least one surgical instrument 20, and a control device 9 is described below.
The at least one surgical instrument 20 includes a pair of antagonistic tendons 31, 32 and at least one degree of freedom P, Y, G; 33. 34; 35. 36 mounted in the surgical instrument 20 for operative connection to a respective motor actuator and a respective connector of the end device 40 to actuate at least one degree of freedom associated therewith (between the at least one degree of freedom P, Y, G described above) to thereby determine an antagonistic effect.
The control means 9 of the system 1 are configured to control the execution of the following actions:
(i) Establishing a single correlation between a set of motions of the motor actuators 11, 12, 13, 14, 15, 16 of the robotic system 1 and corresponding motions of the articulating end effector apparatus 40 of the surgical instrument 20;
(ii) Performing a holding step comprising:
-antagonizing at least one pair of tendons 31, 32 by tensile stress; 33. 34; 35. 36 and maintaining the tendon in a tensile stress state by applying a holding force Fhold to the tendon, said holding force Fhold being adapted to determine the loaded state of the tendon;
Enabling the surgical instrument 20 to enter a teleoperational state upon receipt of a command indicating a willingness to enter teleoperation.
According to various possible embodiments of the system 1, the control device is configured to control the robotic system so as to perform the remote operation preparation method according to any of the previously illustrated embodiments of such a method.
It can be seen that the objects of the invention, as set forth previously, are fully attained by the method set forth above, by means of the features disclosed in detail above, and as already disclosed in the summary of the invention.
Changes and modifications to the embodiments of the method described above may be made by those skilled in the art, or elements may be replaced by functionally equivalent elements, in order to meet contingent needs, without departing from the scope of the following claims. All the features described above as belonging to the possible embodiments can be implemented independently of the other embodiments described.
List of reference numerals
| 1 | Robotic system for tele-surgery |
| 2 | Slave assembly for robotic system |
| 3 | Main control console |
| 9 | Controllers, i.e. control units |
| 10 | Robot system manipulator |
| 11,12,13,14,15,16 | Motor actuator of manipulator |
| 17,18 | Force sensor or load cell |
| 19 | Sterile barrier |
| 20 | Surgical instrument |
| 21,22,23,24,25,26 | Surgical instrument transmission element |
| 27 | Shaft |
| 28 | Pocket piece |
| 29 | Surgical instrument rear end, or drive interface portion |
| 31,32,33,34,35,36 | Tendon |
| 37 | Restraint bodies, or plugs, or covers |
| 40 | End effector device, or articulating tip, or end effector of surgical instrument |
| 41,42,43,44 | Connector with hinged tip |
| 45 | Main body |
| x-x | In the straight direction |
| r-r | Center line |
| P,Y,G | Degrees of freedom of end effector apparatus: corresponding pitching, yawing and gripping |
| Fref | Applied force |
| Fsens | Force detected by force sensor |
| Flow | Low force value |
| Fhigh | High force value |
Claims (49)
1. A method of teleoperational preparation in a teleoperated robotic surgical system (1), the method to be performed during non-operational steps in which the system does not perform teleoperation,
Wherein the robotic system (1) comprises a plurality of motor actuators (11, 12, 13, 14, 15, 16) and at least one surgical instrument (20),
Wherein the at least one surgical instrument (20) comprises:
-an articulating end effector (40) having at least one degree of freedom (P, Y, G);
-at least one pair of antagonistic tendons (31, 32;33, 34;35, 36) mounted in the surgical instrument (20) so as to be operatively connected to respective motor actuators and respective connections of the end effector (40) to actuate at least one of the at least one degrees of freedom (P, Y, G) associated therewith, thereby determining an antagonistic effect;
wherein the method comprises the steps of:
(i) Establishing a single correlation between a set of motions of a motor actuator (11, 12, 13, 14, 15, 16) of the robotic system (1) and corresponding motions of the articulating end effector (40) of the surgical instrument (20);
(ii) Performing a holding step comprising:
-stressing at least one pair of antagonistic tendons (31, 32;33, 34;35, 36) by tensile stress and maintaining the tendons in a tensile stress state by applying a holding force (Fhold) to the tendons, the holding force (Fhold) being adapted to determine a loading state of the tendons;
-providing a command indicating a willingness to enter a remote operation;
-enabling the surgical instrument (20) to enter a teleoperational state.
2. The method of claim 1, comprising, after step (i) -step (ii), the steps of:
(iii) Remote operation is performed by means of the surgical instrument (20) of the robotic system (1).
3. The method of claim 2, wherein the maintaining (ii) and teleoperation (iii) steps are repeated such that the maintaining step (ii) is performed between two adjacent teleoperation steps (iii).
4. The method according to any one of the preceding claims, wherein the surgical instrument (20) further comprises:
a plurality of transmission elements (21, 22, 23, 24, 25, 26), each transmission element being operatively connected to a respective at least one motor actuator (11, 12, 13, 14, 15, 16);
Wherein the step of applying stress is performed by said transmission element (21, 22, 23, 24, 25, 26), operated and controlled by a respective motor actuator;
And wherein the transmission element is preferably rigid.
5. A method according to any one of the preceding claims, wherein a kinematic zero position of each of the motor-actuators (11, 12, 13, 14, 15, 16) is defined, and the method comprises: after said step of stressing at least one pair of antagonistic tendons during said holding step (ii), the following further steps:
-storing the possible positional offset of each electromechanical actuator (11, 12, 13, 14, 15, 16) with respect to the corresponding stored kinematic zero.
6. The method according to any one of the preceding claims, wherein during said maintaining step (ii), said step of stressing at least one pair of antagonistic tendons comprises at least one loading and unloading cycle, wherein each loading and unloading cycle comprises applying a high force (Fhold) to determine the loaded state of said pair of tendons and applying a low force (Flow) to determine the unloaded state of said pair of tendons,
Wherein the high force corresponds to the holding force (Fhold) and the low force (Flow) is a lower force than the holding force (Fhold).
7. The method of claim 6, wherein in each of the loading and unloading cycles, the low force (Flow) is applied first, followed by the high or holding force (Fhold).
8. The method according to claim 6 or 7, wherein in the holding step (ii), between the step of providing a command indicating a desire to enter a remote operation and the step of enabling to enter a remote operation state, the following further steps are provided:
applying the low force (Flow) to the tendon so as to put the tendon under tensile load according to the unloaded state of the loading and unloading cycle:
9. the method according to any of claims 6-8, comprising the further step of:
-detecting the forces applied to all tendons at the exit of the teleoperation step;
-identifying a minimum force (Fmin) among the detected forces;
-putting all the tendons in an intermediate tensile stress state corresponding to a minimum force value (Fmin);
The method preferably further comprises the steps of:
-then putting all the tendons in an unloaded stress state corresponding to the low force (Flow);
And/or
-Then putting all the tendons in a loaded stress state corresponding to the high retention force (Fhold).
10. Method according to claim 9, wherein the step of putting all the tendons in an intermediate stress state corresponding to the minimum force value (Fmin) is performed following a specific and/or different loading and/or unloading curve for each tendon as a function of the detected starting force value for each tendon.
11. The method according to any one of claims 9 or 10, wherein the step of applying the holding force (Fhold) to the tendon comprises:
-placing all the tendons in an intermediate stress state corresponding to the minimum force value (Fmin), wherein each tendon is according to a respective specific load curve depending on a respective detected starting force value such that the load is equally divided between antagonistic tendons of one or more pairs of antagonistic tendons;
-then putting all the tendons in a loaded stress state corresponding to the holding force (Fhold).
12. The method according to any of the preceding claims, wherein the teleoperation step starts with a predefinable teleoperation initiation force (Fwork) applied to the tendon, the initiation force (Fwork) being lower than the high retention force value (Flow),
Wherein, preferably, the predeterminable remote operation initiation force is substantially equal to the low holding force (Flow),
And wherein preferably the transition between the high holding force (Fhold) and the remote-operation initiating force is controlled by the user by activating a control pedal.
13. The method according to any one of the preceding claims, wherein the step of stressing the tendon comprises: the force acting on the tendon is measured or detected during the loading cycle, and the holding force value (Fhold) is reached by the motor-actuator by a feedback force control process based on the detected or measured actual force acting on the tendon.
14. The method according to any one of claims 5-11, wherein the step of stressing the tendons comprises: the force acting on the tendon is measured or detected during the unloading period, and the low force value (Flow) is reached by the motor actuator by a feedback force control process based on the detected or measured actual force acting on the tendon.
15. The method according to any one of claims 1-12, wherein the step of stressing the tendon comprises: -measuring or detecting a positional offset of the motor actuator (11, 12, 13, 14, 15, 16) with respect to a respective initial value predetermined or stored at the end of a previous remote operation step, and-performing a loading cycle by the motor actuator by a feedback position control procedure based on the detected or measured or stored positional offset.
16. The method according to any one of claims 6-12 or 15, wherein the step of stressing the tendon comprises: -measuring or detecting a positional offset of the motor actuator (11, 12, 13, 14, 15, 16) with respect to a respective initial value predetermined or stored at the end of a previous remote operation step, and-performing the unloading cycle by the motor actuator by a feedback position control procedure based on the detected or measured or stored positional offset.
17. A method according to claim 3, wherein during the holding step (ii) at least one pair of tendons is stressed by means of a loaded state corresponding to a gripping action of an end effector (40) of the surgical instrument (20) such that the surgical instrument is in a gripped state during the holding step.
18. The method according to any one of claims 5-15, wherein the holding step (ii) comprising a loading and unloading cycle is performed only on a subset of tendons that do not involve actuation of the gripping degrees of freedom.
19. The method according to any of the preceding claims, wherein the robotic system (1) comprises a control device (9) configured to control the motor actuators (11, 12, 13, 14, 15, 16) to apply a controlled motion and to apply a controlled force to tendons (31, 32, 33, 34, 35, 36), preferably by means of transmission elements (21, 22, 23, 24, 25, 26) operatively connected to the respective tendons.
20. Method according to claim 19, wherein the kinematic zero position of each of the motor-actuators (11, 12, 13, 14, 15, 16) is defined, the method being adapted for a non-operating step between two remote operating periods of the robotic system (1),
Wherein at the beginning of the non-operative step, the method comprises the further steps of:
-storing the position of the end effector (40) at the end of the previous teleoperation step relative to the kinematic zero as a known kinematic position of the end effector (40) of the surgical instrument (20), wherein the known kinematic position of each of the transmission elements (POS kin-off) corresponds to this position;
-retracting the motor-actuators (11, 12, 13, 14, 15, 16) to remove, for each of the transmission elements (21, 22, 23, 24, 25, 26), the respective positional offset generated in the previous remote operation step;
-applying a respective recalibration force (F) on each transmission element (21, 22, 23, 24, 25, 26) continuously during the whole of the non-operative step of the surgical instrument by means of a feedback control configured to keep the recalibration force (F) constant, so as to determine a respective positional offset (POS FC (t)) on each transmission element (21, 22, 23, 24, 25, 26) resulting from the application of the respective recalibration force (F);
And wherein at the end of the non-operational step at the beginning of the next remote operational step, the method further comprises:
-stopping the application of the recalibration force (F) to each transmission element (21, 22, 23, 24, 25, 26);
-measuring and storing a determined position offset POS FC-off on each transmission element (21, 22, 23, 24, 25, 26) at the end of the non-operative step, following the application of the recalibration force during the immediately-finished non-operative step, and relating the recorded position offset (POS FC-off) for each transmission element (21, 22, 23, 24, 25, 26) to the known kinematic position of the end effector (40);
-applying an operating and a moving force commanded by a control device (9), wherein the control device (9) is configured to determine the control force based on the operator's command and taking into account the stored position offset POS FC-off of each transmission element (21, 22, 23, 24, 25, 26).
21. The method of claim 20, wherein the recalibration force (F) corresponds to the retention force (Fhold).
22. A method according to any one of claims 20 or 21, wherein the step of applying a recalibration force on each transmission element comprises: a force is applied to the transmission element by means of a feedback loop, wherein the feedback signal corresponds to the force applied to the transmission element that is actually detected by a corresponding force sensor operatively connected to the transmission element.
23. The method according to any of claims 20-22, wherein the kinematic zero comprises a fixed offset (PRESTRECH off) caused by another step of pre-conditioning the surgical instrument performed prior to use of the surgical instrument.
24. The method of any of the preceding claims, further comprising a preconditioning step comprising:
(i) Locking at least one of the at least one degree of freedom (P, Y, G) of the end effector (40);
(ii) The tensile stress is applied to the respective at least one tendon operatively connected to the at least one locked degree of freedom by applying an adjusting force (Fref) to the respective transmission element (21, 22, 23, 24, 25, 26) connected to the respective at least one tendon to which the tensile stress is to be applied according to at least one time period.
Wherein the at least one time period comprises:
-at least one low load period, wherein a low adjustment force (Flow) is applied to the respective transmission element, which results in a respective low tensile load on the respective tendon;
-at least one high load period, wherein a high adjustment force (Fhigh) is applied to the respective transmission element, which results in a respective high tensile load on the respective tendon.
25. The method of claim 24, wherein a plurality of said time periods are provided, and wherein respective values of said high adjustment force (Fhigh) increase during at least two adjacent time periods.
26. The method according to any one of claims 24 or 25, wherein a plurality of N time periods is provided in order to determine an alternation between successive low load periods and high load periods, wherein a respective low adjustment force (flow_n) is applied during the low load period of the nth period, and wherein a respective high adjustment force (Fhigh _n) is applied during the high load period of the nth period.
Wherein the low adjustment forces (flow_n) for different time periods correspond to the same predetermined low adjustment force value (Flow), and wherein the high adjustment forces (Fhigh _n) correspond to progressively increasing high adjustment force values (Flow) until a maximum high force value (Fhigh _max) is reached.
27. The method of any of claims 21-26, wherein retracting the motor actuator comprises: any positional offset resulting from a further elastic or plastic compensation step of the conveyor system is removed.
28. The method according to any of the preceding claims, wherein the holding force (Fhold) and/or the recalibration force (F) is in the range of 0.1N to 5N.
29. The method according to any of the preceding claims, wherein the positional offset has to be smaller than a maximum allowable positional offset (dxA),
Wherein preferably the maximum allowable offset (dxA) is in the range 1mm to 5 mm.
30. A teleoperated robotic surgical system (1) comprising a plurality of motor actuators (11, 12, 13, 14, 15, 16), at least one surgical instrument (20) and a control device (9),
Wherein the at least one surgical instrument (20) comprises:
-an articulating end effector (40) having at least one degree of freedom (P, Y, G);
-at least one pair of antagonistic tendons (31, 32;33, 34;35, 36) mounted in the surgical instrument (20) so as to be operatively connected to respective motor actuators and respective connections of the end effector (40) to actuate at least one of the at least one degrees of freedom (P, Y, G) associated therewith, thereby determining an antagonistic effect;
Wherein the control means (9) is configured to control the execution of the following actions:
(i) Establishing a single correlation between a set of motions of a motor actuator (11, 12, 13, 14, 15, 16) of the robotic system (1) and corresponding motions of the articulating end effector (40) of the surgical instrument (20);
(ii) Performing a holding step comprising:
-stressing at least one pair of antagonistic tendons (31, 32;33, 34;35, 36) by tensile stress and maintaining the tendons in a tensile stress state by applying a holding force (Fhold) to the tendons, the holding force (Fhold) being adapted to determine a loading state of the tendons;
-enabling the surgical instrument (20) to enter a teleoperational state upon receipt of a command indicating a willingness to enter teleoperation.
31. The system (1) according to claim 30, after action (i) -action (ii), configured to perform the further step of:
(iii) By means of the surgical instrument (20) of the robotic system (1),
Wherein the steps of maintaining (ii) and teleoperation (iii) are repeated such that the maintaining step (ii) is performed between two adjacent teleoperation steps (iii).
32. The system (1) according to any one of claims 30-31, wherein the surgical instrument (20) further comprises:
a plurality of transmission elements (21, 22, 23, 24, 25, 26), each transmission element being operatively connected to a respective at least one motor actuator (11, 12, 13, 14, 15, 16);
Wherein the transmission elements (21, 22, 23, 24, 25, 26) are operated and controlled by respective motor actuators and are configured to perform a stressing action;
And wherein the transmission element is preferably rigid.
33. The system (1) according to any one of claims 30-32, wherein a kinematic zero position of each of the motor actuators (11, 12, 13, 14, 15, 16) is defined, and wherein the control device (9) is further configured to perform the following further actions during the maintaining step (ii) and after the stressing action on at least one pair of antagonistic tendons:
-storing a possible positional offset of each of the electromechanical actuators (11, 12, 13, 14, 15, 16) with respect to the corresponding stored kinematic zero.
34. The system (1) according to any one of claims 30-33, wherein during said maintaining step (ii) the act of stressing at least one pair of antagonistic tendons comprises at least one loading and unloading cycle, wherein each loading and unloading cycle comprises applying a high force (Fhold) to determine the loaded state of the pair of tendons and applying a low force (Flow) to determine the unloaded state of the pair of tendons,
Wherein the high force corresponds to a holding force (Fhold) and the low force (Flow) is a lower force than the holding force (Fhold),
And wherein in each of said loading and unloading cycles, said low force (Flow) is applied first, followed by said high or holding force (Fhold).
35. The system (1) according to claim 34, wherein in the maintaining step (ii), between the step of providing a command indicating a willingness to enter a teleoperation and the step of enabling to enter a teleoperation state, the control means (9) is configured to perform the following further steps:
-applying the low force (Flow) to the tendon in order to put the tendon under tensile load according to the unloaded state of the loading and unloading cycle.
36. The system (1) according to any one of claims 34 or 35, wherein the control device (9) is configured to perform the further steps of:
-detecting the forces applied to all the tendons at the exit of the teleoperation step;
-identifying a minimum force (Fmin) among the detected forces;
-putting all the tendons in an intermediate stress state corresponding to the minimum force value (Fmin), following a specific and/or different loading and/or unloading curve for each tendon as a function of the detected starting force value for each tendon;
And preferably also performs the steps of:
-then putting all the tendons in an unloaded stress state corresponding to the low force (Flow);
And/or
-Then putting all the tendons in a loaded stress state corresponding to the high retention force (Fhold).
37. The system (1) according to claim 36, wherein the control device (9) is configured to perform the following actions during the step of applying the holding force (Fhold) to the tendon:
-placing all the tendons in an intermediate stress state corresponding to the minimum force value (Fmin), each tendon according to a respective specific load curve depending on a respective detected starting force value, such that the load is equally distributed between antagonistic tendons of one or more pairs of antagonistic tendons;
-then putting all the tendons in a loaded stress state corresponding to the holding force (Fhold).
38. The system (1) according to any one of claims 30-37, configured to start a remote operation with a predefinable remote operation initiation force (Fwork) applied to the tendon below the high retention value (Flow),
Wherein, preferably, the predeterminable remote operation initiation force is substantially equal to a low holding force (Flow),
And wherein preferably said transition between said high holding force (Fhold) and said remote-operation initiating force is controlled by said user by activating a control pedal.
39. The system (1) according to any one of claims 30-38, wherein the step of stressing the tendons comprises: measuring or detecting a force acting on the tendon during the loading period, and reaching the holding force value (Fhold) by the motor-actuator by a feedback force control process based on the detected or measured actual force acting on the tendon,
And/or wherein said step of stressing said tendons comprises: measuring or detecting a force acting on the tendon during the unloading period, and reaching the low force value (Flow) by the motor actuator through a feedback force control process based on the detected or measured actual force acting on the tendon,
And/or wherein said step of stressing said tendons comprises: measuring or detecting a positional offset of the motor actuator (11, 12, 13, 14, 15, 16) relative to a respective initial value predetermined or stored at the end of a previous remote operation step, and performing a loading cycle by the motor actuator by a feedback position control process based on the detected or measured or stored positional offset,
And/or wherein said step of stressing said tendons comprises: -measuring or detecting a positional offset of the motor actuator (11, 12, 13, 14, 15, 16) with respect to a respective initial value predetermined or stored at the end of a previous remote operation step, and-performing an unloading cycle by the motor actuator by a feedback position control procedure based on the detected or measured or stored positional offset.
40. System (1) according to any one of claims 30-39, wherein the control device (9) is configured to control the motor actuator (11, 12, 13, 14, 15, 16) to apply a controlled movement and to apply a controlled force to the tendons (31, 32, 33, 34, 35, 36), preferably by means of a transmission element (21, 22, 23, 24, 25, 26) operatively connected to the respective tendons.
41. The system (1) according to claim 40, wherein a kinematic zero position of each of said motor-actuators (11, 12, 13, 14, 15, 16) is defined, adapted for a non-operative step between two remote operating periods of said robotic system (1),
Wherein the control means (9) is configured to perform the following further steps at the beginning of the non-operative step:
-storing the position of the end effector (40) at the end of the previous teleoperation step relative to the kinematic zero as a known kinematic position of the end effector (40) of the surgical instrument (20), wherein the known kinematic position of each of the transmission elements POS kin-off corresponds to this position;
-retracting the motor-actuators (11, 12, 13, 14, 15, 16) to remove, for each transmission element (21, 22, 23, 24, 25, 26), the respective positional offset generated in the previous remote operation step;
-applying a respective recalibration force (F) on each transmission element (21, 22, 23, 24, 25, 26) continuously during the whole of the non-operative step of the surgical instrument by means of a feedback control configured to keep the recalibration force (F) constant, so as to determine a respective positional offset (POS FC (t)) on each transmission element (21, 22, 23, 24, 25, 26) due to the application of the respective recalibration force (F);
And wherein the control means (9) are configured to perform at the end of the non-operative step at the beginning of the next remote operative step the following further actions:
-stopping the application of the recalibration force (F) to each transmission element (21, 22, 23, 24, 25, 26);
-measuring and storing a determined position offset POS FC-off on each transmission element (21, 22, 23, 24, 25, 26) at the end of the non-operative step, following the application of the recalibration force during the immediately-finished non-operative step, and relating the recorded position offset (POS FC-off) for each transmission element (21, 22, 23, 24, 25, 26) to the known kinematic position of the end effector (40);
-applying an operation and a power commanded by a control device (9), wherein the control device (9) is configured to determine the control force based on the operator's command and taking into account the stored position offset POS FC-off of each transmission element (21, 22, 23, 24, 25, 26).
42. The system (1) according to claim 41, wherein the recalibration force (F) corresponds to the retention force (Fhold),
And/or wherein the step of applying a recalibration force on each of the transmission elements comprises: applying a force to the transmission element by means of a feedback loop, wherein the feedback signal corresponds to the force applied to the transmission element that is actually detected by a corresponding force sensor operatively connected to the transmission element,
And/or wherein the kinematic zero comprises a fixed offset (PRESTRECH off) caused by another step of preconditioning the surgical instrument performed prior to use of the surgical instrument.
43. The system (1) according to any one of claims 30-42, wherein the control means (9) is configured to control a pre-conditioning step comprising:
(i) Locking at least one of the at least one degree of freedom (P, Y, G) of the end effector (40);
(ii) The tensile stress is applied to the respective at least one tendon operatively connected to the at least one locked degree of freedom by applying an adjusting force (Fref) to the respective transmission element (21, 22, 23, 24, 25, 26) connected to the respective at least one tendon to which the tensile stress is to be applied according to at least one time period.
Wherein the at least one time period comprises:
-at least one low load period, wherein a low adjustment force (Flow) is applied to the respective transmission element, which results in a respective low tensile load on the respective tendon;
-at least one high load period, wherein a high adjustment force (Fhigh) is applied to the respective transmission element, which results in a respective high tensile load on the respective tendon.
44. The system (1) according to claim 43, wherein a plurality of said time periods are provided, and wherein respective values of said high adjustment force (Fhigh) increase during at least two adjacent time periods.
45. The system (1) according to any one of claims 43 or 44, wherein a plurality of N time periods is provided in order to determine an alternation between successive low load periods and high load periods, wherein a respective low adjustment force (flow_n) is applied during the low load period of the nth period, and wherein a respective high adjustment force (Fhigh _n) is applied during the high load period of the nth period.
Wherein the low adjustment forces (flow_n) for different time periods correspond to the same predetermined low adjustment force value (Flow), and wherein the high adjustment forces (Fhigh _n) correspond to progressively increasing high adjustment force values (Flow) until a maximum high force value (Fhigh _max) is reached.
46. The system (1) according to any one of claims 41-45, wherein the step of retracting the motor actuator comprises: any positional offset resulting from a further elastic or plastic compensation step of the conveyor system is removed.
47. The system (1) according to any one of claims 30-46, wherein the retention force (Fhold) and/or the recalibration force (F) is in the range of 0.1N to 5N.
48. The system (1) according to any one of claims 30-47, wherein the positional offset has to be smaller than a maximum allowable positional offset (dxA), wherein preferably the maximum allowable offset (dxA) is in the range of 1mm to 5mm
49. The system (1) according to any one of claims 30-49, wherein the tendon is a polymer tendon made of woven polymer fibers.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT102021000015902 | 2021-06-17 |
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| Publication Number | Publication Date |
|---|---|
| CN117940085A true CN117940085A (en) | 2024-04-26 |
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